AN3064

Battery monitoring functions

Doc ID 16263 Rev 1

5/15

2

Battery monitoring functions

The STC3100 includes the following battery monitoring functions.

●

A Coulomb counter for automatic computation of the battery’s charge variation: this is

done by integrating the battery current versus the time and accumulating the resulting

charge variation into the accumulator register. The last current measurement is always

available.

●

Automatic periodic measurement of the battery voltage.

●

Automatic periodic measurement of the temperature using the STC3100’s internal

sensor.

The battery monitoring functions are controlled by the GG_RUN bit in the REG_MODE

register. Since GG_RUN is reset at power-up, the battery monitoring functions are disabled,

ensuring a low standby current when the battery is inserted until the application is started.

The Coulomb counter function uses a 12/14-bit ADC and runs continuously after it has been

enabled by the GG_RUN bit.

Values held in consecutive registers (such as the charge value in the REG_CHARGE_LOW

integrity. Multiple values can be read in one I²C access; all values will then be consistent,

that is, will be relative to the same time.

2.1

Coulomb counter operation

The voltage drop between the CG and GND pins is integrated during a conversion period

and input to a 12- to 14-bit AD converter. The output conversion is accumulated into a 28-bit

accumulator. The system controller can control the Coulomb counter and read the data